Dab tsi yog polyurethane foaming pab?
Foaming aids yog qhov tseem ceeb hauv kev tsim cov polyurethane ua npuas ncauj yas, nrog rau cov catalysts, ua npuas ncauj stabilizers, foaming agents, thiab lwm yam. Qee cov additives yog xaiv tau thiab siv thaum tsim nyog, xws li nplaim hluav taws, saw extenders/cross-linking agents, antioxidants, light stabilizers. , foam softeners, cell openers, fillers, xim pastes, antistatic agents, hydrolysis stabilizers, ua npuas ncauj ua ke cov ntaub ntawv cia stabilizers, thiab lwm yam.
1. Foaming agent
Dej yog ib qho tseem ceeb ua npuas ncauj hauv kev tsim cov ntaub ntawv polyurethane. Nws belongs rau ib tug chemical foaming agent. Nws reacts nrog isocyanate los tsim cov pa roj carbon dioxide kom nthuav dav, ua npuas ncauj, thiab ua kom cov ntaub ntawv viscoelastic ua npuas ncauj, ntau yam polyurethane ua npuas ncauj yas.
Nyob rau hauv kev tsim cov polyurethane mos ua npuas ncauj, thiaj li yuav tau txais tsawg-density soft foam plastics, thiab nyob rau tib lub sij hawm kom tsis txhob ua npuas ncauj nruj nreem vim dej ntau dhau, nws yog ib qhov tsim nyog los tswj tus nqi ntawm cov dej thiab ntxiv ib tug tsim nyog tus nqi ntawm lub cev. foaming tus neeg sawv cev ua tus pab cuam foaming.
2. Ua npuas ncauj stabilizer
Thaum tsim polyurethane ua npuas ncauj yas, ua npuas ncauj stabilizer (los yog ua npuas ncauj leveler) yog ib qho tseem ceeb tivthaiv. Nws tuaj yeem ua rau kom muaj kev sib nrig sib solubility ntawm txhua yam, ua si lub luag haujlwm ntawm emulsifying ua npuas ncauj cov ntaub ntawv, stabilizing ua npuas ncauj thiab regulating ua npuas ncauj hlwb. Ua npuas ncauj stabilizer belongs rau surfactants, uas tau muab faib ua ob pawg: non-silicon tebchaw thiab organosilicon tebchaw.
Feem ntau ntawm cov ua npuas ncauj stabilizers siv tam sim no yog polysiloxane oxidized olefin block copolymers, uas yog los ntawm polyether hloov silicone surfactants, thiab qee zaum feem ntau hu ua "silicone roj" hauv kev lag luam. Vim tias hom surfactant no muaj ntau yam kev sib txawv ntawm cov qauv sib txawv thiab siv tau zoo, polyether hloov silicone surfactants tau dav siv ua npuas dej stabilizers hauv polyurethane ua npuas ncauj plastics kev lag luam.
3. Cell openers
Cell openers yog ib hom tshwj xeeb ntawm surfactants, feem ntau muaj hydrophobic thiab hydrophilic ntu lossis pawg. Lawv txoj haujlwm yog txhawm rau txo qhov nro ntawm cov npuas dej, txhawb kev tawg ntawm lub qhov hws, nce qhov porosity ntawm polyurethane ua npuas ncauj, thiab txhim kho lub shrinkage ntawm mos, semi-rigid, thiab rigid foam khoom tshwm sim los ntawm kaw hlwb.
Thaum ntxov, hydrophobic kua paraffin, polybutadiene, dimethyl polysiloxane, thiab lwm yam yuav siv tau ua npuas ncauj stabilizers thiab cell openers. Paraffin dispersions thiab polyethylene oxide kuj tseem siv tau los ua cell openers. Tam sim no, polyoxypropylene-ethylene oxide copolyethers thiab polyoxyolefin-polysiloxane copolymer nrog cov tshuaj tshwj xeeb feem ntau yog siv los ua cell openers.
4. Cov tshuaj tsw qab
Kev siv cov softeners nyob rau hauv zus tau tej cov high-water-cov ntsiab lus polyurethane mos foams yuav suppress qhov teeb meem ntawm ua npuas ncauj txhav los ntawm ntau urea pawg. Foam softening modifiers muaj cov nyhuv softening. Kev siv cov softeners tuaj yeem txo cov isocyanate siv thiab yog li txo qhov tawv ntawm cov npuas dej, thiab siv rau hauv kev tsim cov mos polyurethane foams. Cov khoom muag muag feem ntau muaj cov polyethers tshwj xeeb, polyols tshwj xeeb, thiab dej.